1. Field of the Invention
This invention relates generally to waveguides such as are usually used for transmitting microwave signals, and more particularly is directed to improvements in waveguide elements which may be assembled in end-to-end relation to form a waveguide line of substantial length.
2. Description of the Prior Art
Microwave signals are usually transmitted by a waveguide line which is constructed of a plurality of waveguide elements assembled together in end-to-end relation. Several types of waveguide elements have been proposed. Usually, these waveguide elements each consist of a tubular portion of rectangular or circular cross-section and flanges provided at the ends of the tubular portion so that successive waveguide elements can be secured together in end-to-end relation by means of their adjacent flanges to form a waveguide line of substantial length which may be joined to other related microwave devices by means of the flanges on the waveguide elements at the ends of such line. The tubular portions of the waveguide elements function both to form a transmission path for a microwave signal and to make the waveguide line self-supporting or rigid. The existing waveguide elements are usually formed entirely of metal, particularly of copper or an alloy thereof. Since the thicknesses of the tubular portions and flanges of such waveguide elements are dictated by their function of making the waveguide line self-supporting or rigid, rather than by the function of forming a transmission path for the microwave signal, for which purpose only very thin metal structures are sufficient, the existing waveguide elements formed entirely of metal are undesirably heavy and, therefore, difficult to handle, as well as being relatively costly.